Why can't we go faster than the speed of light?
Oh boy. This is going to get rough, so strap yourselves in. It's basically a math-thing, but the reason we can't go faster than light is because it would require all the energy that ever existed or will exist to move us because we'd be as heavy as everything that ever existed or will exist. Got it?
Fine, here's the rest. When you move, you're putting energy into whatever is moving. Let's say I'm crusing around in my tricked out Honda Civic with neon running lights and rear spoiler. When I hit the gas, all the ladies look my way. Also, the car becomes energetic and moves forward. I put energy into the car. Simple so far, no?
Relativity makes my butt look fat
Although most of us don't understand everything Einstein talked about, we all know his famous theory: energy (e) is equal to mass (m) times the speed of light (c) squared, or e=mc2. That means energy is equal to mass. They are the same thing, sort of. Enough for the purpsoes of this question, at least.
What's mass? It's how much of something there is in that something. For example, I've got more mass than Gary Coleman (I'm bigger, thank God) but not as much as Rush Limbaugh (I'm thinner, thank God).
Weight is how heavy a mass is in gravity. That's why I would weigh less on the Moon; less gravity, less weight. But the amount of me in me (my mass) stays the same. I would only lose mass if a gator bit off my arm, or if I actually started exercising and lost some fat. Little chance of both, really.
Back to me in my Civic. I hit the gas, which puts energy into the car. Since energy is equal to mass, I'm increasing the mass of my Civic a tiny, tiny bit. So everytime I push the pedal closer to the metal, my beautiful Civic gets a tiny bit heavier.
Why it's easier to tip a terrier than a cow
Quiz time: which takes more gas to go 65 mph, a tiny Civic or a huge 18-wheel truck? Correct! The truck takes more gas because it's more massive. You're so smart.
When I hit the gas on my Civic, it adds mass to the car. It will now take more gas to go faster since it's heavier; it's inching closer towards weighing the same as that truck. This is no problem if I only want to accelerate to normal car speeds, because the amount of mass added to the Civic through energy is small enough to be ignored.
But what if we wanted to drive to the Moon? We'd have to go fast enough on the Trans-Lunar Turnpike to break the Earth's gravity, accelerating to roughly 14,000 mph (I think that's two tanks of gas every second). At these speeds, the build up of additional mass starts demanding attention.
My Big, Fat, Relativistic Civic
As we accelerate faster, the car gets heavier (more energy equals more mass). If the Civic is heavier, we need to use more energy to accelerate. That energy starts to add more mass, which requires more energy, which adds more mass, which requires more energy, and on and on until, literally, infinity.
Here's what I mean. When we plug in some numbers for energy and mass in a fancy equation, here's what the math says about driving my car faster than the speed of light:
- I need energy to move my car because the car is heavy
- the more energy I use, the heavier my car becomes
- the heavier my car becomes, the more energy I need to move it faster
- but the more energy I use, the heavier my car becomes
- this spirals out of control; energy and mass keep increasing until ...
- ... they both equal infinity. My car is infinitly heavy, so it needs an infinite amount of energy to move it at the speed of light.
And you thought reality TV was stupid
What the hell does that mean? How can a car be infinitly heavy? How can my gas tank have an infinite amount of gas? If this sounds stupid, you're right. It is stupid, and that's just to go as fast as light. Going faster than the speed of light is impossible according to the numbers.
See? I told you it's basically a math-thing.
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